The cgroupfs_find_mountpoint() looks up the /proc/mounts file to find
a directory for the given cgroup subsystem. It keeps both cgroup v1
and v2 path since there's a possibility of the mixed hierarchly.
But we can simply use v1 path if it's found as it will override the v2
hierarchy.
Signed-off-by: Namhyung Kim <namhy...@kernel.org>
---
tools/lib/api/fs/cgroup.c | 34 +++++++++++++++-------------------
1 file changed, 15 insertions(+), 19 deletions(-)
diff --git a/tools/lib/api/fs/cgroup.c b/tools/lib/api/fs/cgroup.c
index 889a6eb4aaca..813236d8ca48 100644
--- a/tools/lib/api/fs/cgroup.c
+++ b/tools/lib/api/fs/cgroup.c
@@ -12,7 +12,7 @@ int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const
char *subsys)
{
FILE *fp;
char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
- char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
+ char path_v2[PATH_MAX + 1];
char *token, *saved_ptr = NULL;
fp = fopen("/proc/mounts", "r");
@@ -22,45 +22,41 @@ int cgroupfs_find_mountpoint(char *buf, size_t maxlen,
const char *subsys)
/*
* in order to handle split hierarchy, we need to scan /proc/mounts
* and inspect every cgroupfs mount point to find one that has
- * perf_event subsystem
+ * the given subsystem. If we found v1, just use it. If not we can
+ * use v2 path as a fallback.
*/
- path_v1[0] = '\0';
path_v2[0] = '\0';
while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s
%"__stringify(PATH_MAX)"s %"
__stringify(PATH_MAX)"s %*d %*d\n",
mountpoint, type, tokens) == 3) {
- if (!path_v1[0] && !strcmp(type, "cgroup")) {
+ if (!strcmp(type, "cgroup")) {
token = strtok_r(tokens, ",", &saved_ptr);
while (token != NULL) {
if (subsys && !strcmp(token, subsys)) {
- strcpy(path_v1, mountpoint);
- break;
+ /* found */
+ fclose(fp);
+
+ if (strlen(mountpoint) < maxlen) {
+ strcpy(buf, mountpoint);
+ return 0;
+ }
+ return -1;
}
token = strtok_r(NULL, ",", &saved_ptr);
}
}
- if (!path_v2[0] && !strcmp(type, "cgroup2"))
+ if (!strcmp(type, "cgroup2"))
strcpy(path_v2, mountpoint);
-
- if (path_v1[0] && path_v2[0])
- break;
}
fclose(fp);
- if (path_v1[0])
- path = path_v1;
- else if (path_v2[0])
- path = path_v2;
- else
- return -1;
-
- if (strlen(path) < maxlen) {
- strcpy(buf, path);
+ if (path_v2[0] && strlen(path_v2) < maxlen) {
+ strcpy(buf, path_v2);
return 0;
}
return -1;
--
2.29.2.684.gfbc64c5ab5-goog
